Question

What are particulate pollutants? Explain any three.

Answer 1

1. Particulate pollutants are small solid particles, and liquid droplets suspended in air.
   Examples:
   dust, pollen, smoke, soot and liquid aerosols.
2. Types of Particulates:
   Particulates in the atmosphere may be of two types:
   1. viable particulate and
   2. non-viable particulate.
3. The viable particulates are small size living organisms such as bacteria, fungi, moulds and algae which are dispersed in air.
4. The non-viable particulates are small solid particles and liquid droplets suspended in air. There are four types of non-viable particulates in the atmosphere. They are
   1. Smoke
   2. Dust
   3. Mist
   4. Fumes
5. Smoke:
   Smoke particulate consists of solid particles formed by the combustion of organic matter. For example, cigarette smoke, oil smoke, smokes from the burning of fossil fuels, garbage and dry leaves.

6. Dust:
   It is composed of fine solid particles produced during the crushing and grinding of solid materials. For example, sand from sand blasting, saw dust from wood works and fly ash from power generating units.

7. Mist:
   They are formed by particles of sprayed liquids and condensation of vapours in air. For example, sulphuric acid mist, herbicides and insecticides sprays can form mists.

8. Fumes:
   They are obtained by condensation of vapours released during sublimation, distillation, boiling and calcination and by several other chemical reactions.
   For example:
   organic solvents, metals and metallic oxides.